• Title/Summary/Keyword: 과부하 방지장치

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Development of Greenhouse Environment Monitoring & Control System Based on Web and Smart Phone (웹과 스마트폰 기반의 온실 환경 제어 시스템 개발)

  • Kim, D.E.;Lee, W.Y.;Kang, D.H.;Kang, I.C.;Hong, S.J.;Woo, Y.H.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.18 no.1
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    • pp.101-112
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    • 2016
  • Monitoring and control of the greenhouse environment play a decisive role in greenhouse crop production processes. The network system for greenhouse control was developed by using recent technologies of networking and wireless communications. In this paper, a remote monitoring and control system for greenhouse using a smartphone and a computer with internet has been developed. The system provides real-time remote greenhouse integrated management service which collects greenhouse environment information and controls greenhouse facilities based on sensors and equipments network. Graphical user interface for an integrated management system was designed with bases on the HMI and the experimental results showed that a sensor data and device status were collected by integrated management in real-time. Because the sensor data and device status can be displayed on a web page, transmitted using the server program to remote computer and mobile smartphone at the same time. The monitored-data can be downloaded, analyzed and saved from server program in real-time via mobile phone or internet at a remote place. Performance test results of the greenhouse control system has confirmed that all work successfully in accordance with the operating conditions. And data collections and display conditions, event actions, crops and equipments monitoring showed reliable results.

Performance Analysis of Multiple Access Protocol for Maritime VHF Data Exchange System (VDES) (해상 초단파 대역 데이터 교환 시스템을 위한 다중 접속 방식의 성능 분석 연구)

  • Yun, Changho;Cho, A-Ra;Kim, Seung-Geun;Lim, Yong-Kon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.12
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    • pp.2839-2846
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    • 2014
  • New VHF band for use in VDE is determined by WRC-12 due to the overload of AIS VDL, and the system characteristics of the VDE is recommended as ITU-R M. 1842-1. CS-TDMA, a multiple access method of AIS class B, is recommended as that of the VDE. It is inefficient for CS-TDMA just applying the report interval used in AIS class B to transmit high speed data with higher payload in the aspect of efficiency. In this paper, a simulation is executed in order to determine adequate report interval according to the number of active ships that affects directly network traffic. To this end, the performance of CS-TDMA, which includes the number of received packets, reception success rate, channel utilization, and collision rate, is investigated via a simulation.